White Buffalo Grass or Blue Panicgrass * Witbuffelgras * Panicum coloratum var. coloratum

By USDA NRCS James E. "Bud" Smith Plant Materials Center -  https://commons.wikimedia.org/w/index.php?curid=19625373

Sources:

(*) https://en.wikipedia.org/wiki/Panicum_coloratum
(*) https://www.inaturalist.org/taxa/600553-Panicum-coloratum-coloratum